LU-12222 lnet: Primary NID of lolnd NID is the lolnd NID

We want Lustre traffic that is intended for the local peer to be sent
and received over the lolnd. The function ptlrpc_uuid_to_peer() will
currently resolve a NID to the lolnd NID, but ptlrpc_connection_get()
will overwrite this selection with the result from LNetPrimaryNID().

Have LNetPrimaryNID return the lolnd NID when it is passed the lolnd
NID.

Lustre-change: https://review.whamcloud.com/38313
Lustre-commit: 33d2e44e



HPE-bug-id: LUS-8457
Signed-off-by: Chris Horn <hornc@cray.com>
Change-Id: I02708bb45f8440091782ca7886bac7656efb0223
Reviewed-on: https://review.whamcloud.com/38864

Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>

lnet/lnet/peer.c

@@ -1115,6 +1115,9 @@ LNetPrimaryNID(lnet_nid_t nid)
 	int rc = 0;
 	int cpt;
 
+	if (nid == LNET_NID_LO_0)
+		return LNET_NID_LO_0;
+
 	cpt = lnet_net_lock_current();
 	lpni = lnet_nid2peerni_locked(nid, LNET_NID_ANY, cpt);
 	if (IS_ERR(lpni)) {